Polymeric binders for ink jet inks

ABSTRACT

An emulsion-polymerized addition copolymer formed from a monomer mixture comprising ethylenically unsaturated monomers, including from more than 4 to 15 wt % based on the weight of said mixture of at least one ethylenically unsaturated carboxylic acid functional monomer, and from 0.05 to 5 wt % based on the weight of said mixture of at least one polymerizable surfactant monomer comprising hydrophobic and hydrophilic functional groups, wherein said hydrophobic functional group comprises a polymerizable group within it, is useful as a binder in an ink jet ink having improved print quality.

[0001] This invention concerns polymeric binders which are suitable foruse in ink jet inks. More specifically, this invention relates topolymeric binders formed by polymerization of a monomer mixturecomprising a polymerizable surfactant monomer.

[0002] Certain ink jet inks comprise a liquid medium, a colorant, suchas a pigment or dye, a binder or resin to aid in dispersing the pigmentin the medium and to affix the colorant to the print surface. In orderto create more durable print quality, particularly in terms ofcolor-fastness and water- and rub-resistance of the printing ink, therehas been interest in preparing ink jet inks in which the colorant is aninsoluble pigment, rather than a water soluble dye. The latter aregenerally absorbed to some degree by the paper or other print medium,but due to their inherent water-solubility do not offer goodwaterfastness. Pigment-based inks are generally deposited on the surfaceof the print medium, making them susceptible to removal by water orabrasion. However, as a result of the physical properties of pigments,pigment based ink compositions have a tendency to have a low wet-rubresistance and low highlighter resistance.

[0003] The term “wet-rub,” as used herein, means applying abrasivepressure across the printed substrate with a wetted paper facial tissueand measuring any smear created thereby; wet-rub differs fromwaterfastness because abrasion is used. The term “highlighterresistance,” as used herein, means applying abrasive pressure across aprinted substrate with a commercially available highlighting marker andmeasuring any smear created thereby; an example of such marker isSanford Corp. Major Accent brand highlighting markers. The term “printquality”, as used herein, means an accumulative evaluation of theoverall performance of an ink jet ink as measured by the appearance of aprinted page of combined text and graphics, including edge sharpness,bleed, feathering, optical density, wet-rub resistance, highlighterresistance and print operability. The term “print operability”, as usedherein, means an accumulative evaluation of printer performance,including print appearance and uniformity, page after page longevity ofprint quality and uniformity, nozzle drop outs, print head maintenanceproblems, and the ability to stop and restart printing.

[0004] Polymer binders have been added to ink jet ink compositions toimprove durability, to improve print quality and to reduce colorbleeding and feathering. However, the inclusion of such binders canresult in increased printhead maintenance problems, including cloggingof the nozzles and kogation, i.e. formation of film on or about theheater. Also, polymers may tend to form films on the nozzle plate. Theaddition of polymers to ink jet ink compositions also may causedecreased pigment dispersion stability and interference with bubbleformation.

[0005] EP-A-0869 160 discloses an inkjet ink formulation with colorant,vehicle and resin emulsion containing ionic carboxylic groups on thesurface of resin emulsion particles to cause disassociation of thecolorant and resin particles. The resin has 1 to 40 wt. % “carboxylicacid groups”, and Tg of 0 to 120° C. Exemplified embodiments of theresin include copolymers of butyl acrylate, methyl methacrylate and(meth)acrylic acid, with 3 to 20 wt. % acid, Tg of 53 to 95° C. andparticle size of 63 to 235 nm, utilizing high Tgs and low particlesizes.

[0006] EP-A-0747456 discloses a method for providing a waterbornecoating composition, such as a paint, having improved color acceptance.The coating composition contains an emulsion-polymerized additionpolymer formed from a mixture of monomers including a polymerizablesurfactant monomer. There is no disclosure of the use of the additionpolymer in an ink.

[0007] It is an object of the present invention to provide a polymericbinder for use with a colorant to form an ink jet ink that demonstratesan improved print quality, as expressed by an improvement in one or moreproperties used to determine print quality, which improvement isachieved without any significant detrimental effect on the otherproperties used to determine print quality.

[0008] In accordance with the present invention, there is provided apolymeric binder suitable for use in an ink composition, preferably anink jet ink composition, comprising a colorant and a polymeric binder,wherein the polymeric binder is an emulsion-polymerized additioncopolymer formed from a monomer mixture comprising ethylenicallyunsaturated monomers including from more than 4 to 15 wt % based on theweight of said mixture of at least one ethylenically unsaturatedcarboxylic acid functional monomer, and from 0.05 to 5 wt % based on theweight of said mixture of at least one polymerizable surfactant monomercomprising hydrophobic and hydrophilic functional groups, wherein saidhydrophobic functional group comprises a polymerizable group within it.

[0009] In another aspect, there is provided an ink composition,preferably an ink jet composition, comprising a colorant and a polymericbinder, wherein the polymeric binder is an emulsion-polymerized additioncopolymer formed from a monomer mixture comprising ethylenicallyunsaturated monomers including from more than 4 to 15 wt % based on theweight of said mixture of at least one ethylenically unsaturatedcarboxylic acid functional monomer, and from 0.05 to 5 wt % based on theweight of said mixture of at least one polymerizable surfactant monomercomprising hydrophobic and hydrophilic functional groups, wherein saidhydrophobic functional group comprises a polymerizable group within it.

[0010] In yet another aspect of the present invention, there is providedthe use of an emulsion-polymerized addition copolymer, formed from amonomer mixture comprising ethylenically unsaturated monomers includingfrom more than 4 to 15 wt % based on the weight of said mixture of atleast one ethylenically unsaturated carboxylic acid functional monomerand from 0.05 to 5 wt % based on the weight of said mixture of at leastone polymerizable surfactant monomer comprising hydrophobic andhydrophilic functional groups, wherein said hydrophobic functional groupcomprises a polymerizable group within it, as a polymeric binder in anink composition, preferably an ink jet composition, to improve the printquality of said ink composition.

[0011] Surprisingly, ink jet inks comprising a binder of the presentinvention demonstrate improved print quality over binders of similarcomposition but which do not comprise a polymerized surfactant monomer.In addition, ink jet inks of the present invention may demonstrate animproved optical density.

[0012] Polymerizable surfactant monomers are known in the art. They aresurface active compounds having a polymerizable group, such as an allyl,acryl, methallyl or methacryl group (herein also referred to as(meth)acryl or (meth)allyl group), and which may be used as anemulsifier in an emulsion polymerization. Thus, the polymerizablesurfactant functions as both a surfactant and as a comonomer. Thepolymerizable surfactant may be cationic, anionic or nonionic. Suitablepolymerizable surfactant monomers comprising hydrophobic and hydrophilicfunctional groups, wherein said hydrophobicfunctional group comprises apolymerizable group within it include, for example, anionic surfactantmonomers such as sulphates, phosphates, sulphosuccinate half esters, andsulphosuccinate diesters bearing copolymerizable reactive groups andnonionic surfactant monomers such as nonylphenoxy propenylpolyethoxylated alcohols (for example as Noigen RN-20 from Dai-ichiCorp). Preferred polymerizable surfactant monomers are nonylphenoxypropenyl polyethoxylated sulphate (for example as Hitenol from Dai-ichiCorp); sodium alkyl allyl sulphosuccinate (for example as Trem LF-40from Henkel Corp); ammonium di-(tricyclo(5.2.1.0 2,6) dec-3-en-(8 or9)oxyethyl) sulfosuccinate; and ammonium di-(tricyclo(5.2.1.0 2,6)dec-3-en-(8 or 9) sulfosuccinate. Additionally, the ammonium and metalsalts of unsaturated C₆ to C₃₀ organic acids may be suitable, these maybe used alone or in combination with the above surfactants. Examples ofthese acids are: alpha methyl cinnamic acid, alpha phenyl cinnamic acid,oleic acid, lineolic acid (as described in U.S. Pat. No. 5,362,832),rincinoleic acid, the unsaturated fraction of Tall oil rosin and fattyacids, disproportionated rosin acid, soybean oil fatty acids, olive oilfatty acids, sunflower oil fatty acids, linseed oil fatty acids,safflower oil fatty acids, sorbitan mono-oleate, abietic acid,poly(oxyethylene) sorbitol sesquioleate, and Empol 1010 Dimer Acid.Suitable polymerizable surfactant monomers also include, for example,maleate derivatives (as described in U.S. Pat. No. 4,246,387), and allylderivatives of alkyl phenol ethoxylates (as described in JP-62227435).

[0013] The amount of polymerizable surfactant monomer in the monomer mixis preferably from 0.075 to 2 wt %, more preferably 0.075 to 0.5 wt %,based on the weight of said mixture.

[0014] The ethylenically unsaturated carboxylic acid functional monomersare preferably C₃ to C₂₀ ethylenically unsaturated carboxylic acids,more preferably monomers selected from the group consisting of acrylicacid, methacrylic acid, itaconic acid, fumaric acid, maleic acid andanhydrides of such acids; their basic salts e.g. the ammonium,quaternary alkyl ammonium, lithium, sodium and potassium salts thereof;and mixtures of such monomers. Alternatively, the ethylenicallyunsaturated carboxylic acid monomer may be an oligomer of acrylic ormethacrylic acid, preferably having a molecular weight of no more than5000 Daltons.

[0015] The amount of ethylenically unsaturated carboxylic acid monomerin the monomer mix is preferably from more than 4 to 10 wt %, morepreferably from 4.5 to 9 wt %, based on the weight of said mixture.

[0016] Other ethylenically unsaturated monomers suitable for use in saidmonomer mix include one or more monomers selected from, but not limitedto: substituted e.g. hydroxy- or acetoacetoxy-substituted andunsubstituted (C₁ to C₅₀, preferably C₁-C₂₂, most preferably C₁ to C₁₈)alkyl (meth) acrylates, styrene and substituted styrenes, vinylacrylates, vinyl acetates, fluoromethacrylates, acrylamide, substitutedacrylamides, methacrylamides, substituted methacrylamides, andcombinations thereof. Among the esters of acrylic acid and methacrylicacid, preferred monomers include methyl acrylate, ethyl acrylate, propylacrylate, butyl acrylate, ethylhexyl acrylate, lauryl acrylate, methylmethacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, lauryl methacrylate, isobutylene methacrylate,hydroxyethyl (meth)acrylate and acetoacetoxy (meth)acrylate. Mostpreferably, the monomers are selected from the group consisting ofmethyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethylmethacrylate, propyl methacrylate, butyl methacrylate, laurylmethacrylate, isobutylene methacrylate, styrene, acrylamide, vinylacrylate, vinyl acetate, hydroxyethyl acrylate and hydroxyethylmethacrylate.

[0017] In one embodiment, the binder comprises an addition copolymer ofethylhexyl acrylate, methyl methacrylate, methacrylic acid and sodiumalkyl allyl sulphosuccinate.

[0018] Preferably the binder comprises an addition polymer with a glasstransition temperature, Tg, of at least −40° C., more preferably in therange from −35 to about 120° C., yet more preferably in the range from−35 to 20° C., and even more preferably in the range from −30 to 10° C.Tg can be determined by the Fox equation.

[0019] In a preferred embodiment, the polymer binder comprises a singlestage addition polymer with an average diameter in the range from about100 to 400 nm. More preferably, the average diameter is in the range 200to 350 nm. The average particle diameter may be determined by a lightscattering technique, such as by employing a Brookhaven InstrumentsCorporation, “BI-90 Particle Sizer” analyzer.

[0020] The particle size distribution of the binder polymer may beunimodal, bimodal or polymodal, but modality is not considered importantto the practice of this invention.

[0021] The molecular weight of the polymeric binder is not critical.However, it has been found that the binder polymers preferably has amolecular weight in the range from about 10,000 to about 2,000,000Daltons; more preferably, 50,000 to 1,000,000 Daltons. The molecularweight as used herein is defined as the weight average molecular weightand may be determined by gel permeation chromatography in THF assolvent.

[0022] The ink composition of the present invention may further compriseadditional components including without limitation process aids such asother (free) surfactants, protective colloids, and other stabilizersknown to those skilled in the art. Suitable surfactants, for example,include sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodiumdioctyl sulfosuccinate, and ammonium perfluroralkyl sulfonates, TritonX-100, Triton X-405, and polyoxyethylenated polyoxypropylene glycols.

[0023] The addition polymer may be prepared by a conventionalpersulfate-initiated thermal process known in the art such as batch,semi-batch, gradual addition or continuous, for example as described inEP-A-0747456. The monomers are polymerized to preferably greater than99% conversion and then the reaction is cooled to room temperature(20-25° C.) after the addition of the appropriate amount of neutralizingbase to control pH. The pH is adjusted to between pH 7-10, morepreferably between pH 8-9, with neutralizer such as, for example,ammonia, lithium hydroxide, sodium hydroxide, potassium hydroxide orcombinations of these neutralizers.

[0024] The binder may be incorporated in an ink composition, preferablyan ink jet ink composition, comprising, for example, pigment, binder andan aqueous medium. Preferably, the binder is present at a level of 0.1to 10 weight percent, preferably, 0.5 to 8 weight percent, morepreferably 1 to 5 weight percent relative to the total weight of the inkcomposition. The aqueous carrier may be water; preferably, deionizedwater. In one embodiment, the aqueous carrier is present at from about40% to about 95%, preferably from about 55% to about 80%, mostpreferably, from about 70% to about 80% by weight of the inkcomposition. Selection of a suitable mixture for the ink compositionusing the binder of the present invention depends upon the requirementsof the specific ink being formulated, such as the desired surfacetension and viscosity, the pigment used, the drying time required forthe pigmented ink and the type of paper onto which the ink will beprinted.

[0025] The ink composition using the binder of the present invention mayalso include water miscible materials such as humectants, dispersants,penetrants, chelating agents, co-solvents, defoamers, buffers, biocides,fungicides, viscosity modifiers, bactericides, surfactants, anti-curlingagents, anti-bleed agents and surface tension modifiers, all as is knownin the art. Useful humectants include ethylene glycol, 1,3 propanediol,1,4 butanediol, 1.4 cyclohexanedimethanol, 1,5 pentanediol, 1,6hexanediol, 1,8 octanediol, 1,2 propanediol, 1,2 butanediol, 1,3butanediol, 2,3 butanediol, diethylene glycol, triethylene glycol,tetraethylene glycol, polyethylene glycol with average molecular weightof 200, 300, 400, 600, 900, 1000, 1500 and 2000, dipropylene glycol,polyproylene glycol with average molecular weight of 425, 725, 1000, and2000, 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-methyl-2-piperidone,N-ethylacetamide, N-methlpropionamide, N-acetyl ethanolamine,N-methylacetamide, formamide, 3-amino-1, 2-propanediol,2,2-thiodiethanol, 3,3-thiodipropanol, tetramethylene sulfone, butadienesulfone, ethylene carbonate, butyrolacetone, tetrahydrofurfuryl alcohol,glycerol, 1,2,4-butenetriol, trimethylpropane, pantothenol, LiponicEG-1. Preferred humectants are polyethylene glycol with averagemolecular weight of 400 to 1000, 2-pyrrolidone 2,2 thiodiethanol, and1,5 pentanediol. Preferred penetrants include n-propanol, isopropylalcohol, 1,2 hexanediol, and hexyl carbitol.

[0026] Examples of colorants useful in the method of the presentinvention are selected from the group of pigments and dyes generallyuseful in ink jet printing. Suitable organic pigments include carbonblack, azo compounds, phthalocyanine pigments, quinacridone pigments,anthraquinone pigments, dioxazine pigments, indigo, thioindigo pigments,perynone pigments, perylene pigments, and isoindolene. Suitableinorganic pigments include titanium dioxide, iron oxide, and other metalpowders. The amount of pigment is generally determined by the desiredproperties of the ink to be made. Generally, the amount of pigments usedis less that 10% and is typically from 3-8% by weight based on the totalweight of all the components of the ink. The pigment particle size mustbe sufficiently small that pigment particles will not clog the nozzleson the printing device in which the ink is to be used. Typical nozzleopenings on thermal ink jet printers are 30-60 microns in diameter.Preferably, the pigment particle size is from 0.05 to 2 microns, morepreferably not more than one micron and most preferably not more than0.3 microns.

[0027] The amount of humectant used is determined by the properties ofthe ink and may range from 1-30%, preferably from 5-15% by weight, basedon the total weight of all the components in the ink. Examples ofcommonly used humectants useful in forming the ink are: glycols,polyethylene glycols, glycerol, ethanolamine, diethanolamine, alcohols,and pyrrolidones. Other humectants known in the art may be used as well.

[0028] The use of suitable penetrants will depend on the specificapplication of the ink. Useful examples include pyrrolidone, andN-methyl-2-pyrrolidone.

[0029] The amount of defoaming agent in the ink, if used, will typicallyrange from 0.05-0.5% by weight, and is more typically 0.1 wt. %. Theamount required depends on the process used in making the pigmentdispersion component of the ink. Defoaming agents useful in formingaqueous dispersions of pigments are well known in the art andcommercially available examples include Surfynol 104H and Surfynol DF-37(Air Products, Allentown, Pa.).

[0030] The remaining portion of the ink is generally water. The amountof water preferably is from 65-90% by weight, more preferably from75-85% by weight, based on the total weight of all the components in theink.

[0031] The ink compositions of the present invention may be prepared byany method known in the art for making such compositions, for example,by mixing, stirring or agitating the ingredients together using any artrecognized technique to form an aqueous ink. The procedure forpreparation of the ink composition of the present invention is notcritical except to the extent that the ink composition is homogenous.

[0032] One method for preparation is as follows: Mix the aqueouscarrier, humectant(s), surfactant(s) and penetrant(s) for 10 minutes, oruntil homogenous. Prepare pigment-dispersant mixture by milling a 5 to 1ratio of pigment to dispersant to a total of 20% solids in water. Slowlyadd aqueous carrier/humectant/surfactant/penetrant solution topigment-dispersant while pigment(s) remains stirring. Let stir foranother 10 minutes, or until homogeneous. Slowly add the pigmentdispersion/carrier/humectant/surfactant to the polymeric binder withstirring. Continue to stir for 10 minutes or until homogenous. Adjust pHof the resultant ink to 8.2-8.5 (e.g. by adding sufficient 20% NH₄OH).Filter through a 1 micrometer filter. It is expected that the inkcompositions using the binders of the present invention would includeany additives necessary to obtain the desired physical propertiesrequired for the end use of the ink composition such additives includechelating agents, buffers, biocides, fungicides, antioxidants, rheologymodifiers, thickeners, bacteriocides, surfactants, anti-curling agents,anti-bleed agents and surface tension modifiers, all as discussed above.

[0033] The invention in some of its embodiments will now be furtherdescribed by reference to the following examples:

EXAMPLES

[0034] The experiments described below are intended to show the effectof using a polymeric binder comprising a polymerized surfactant monomerin an ink jet ink to improve its print quality. Polymeric binders of thepresent invention comprise a polymerized surfactant monomer comprisinghydrophobic and hydrophilic functional groups, wherein said hydrophobicfunctional group comprises a polymerizable group within it, and areidentified in the worked examples with an asterisk. In each case, thepolymeric binder was formulated into an in jet ink of Formulation 1 orFormulation 2 and the ink was applied to a paper (Hewlett Packard BrightWhite Ink Jet Paper) substrate. Ink Jet Ink Jet Ink Formulation 1 WeightInk Formulation 2 Weight n-MethylPyrollidone  6.5 g n-MethylPyrollidone 6.4 g PolyEthyleneGlycol  4.0 g PolyEthyleneGlycol  4.0 g Dispersion 25.0 g Dispersion  24.8 g Propanediol  10.2 g Propanediol  4.8 gPolymer Binder  20.0 g Liponics EG-1  2.0 g Water  54.3 g Surfynol 104E 0.4 g Total 120.0 g Polymer Binder  20.0 g Water  57.6 g Total 120.0 g

[0035] Liponics EG-1 is a dispersant available from Lipo Chemicals, NewJersey.Surfynol 104E is a dispersant available from Air Products, PA.

[0036] Several different ink jet printers were used. These include theHewlett Packard DeskJet 540, 690C, and 890C printers. All of these arethermal (bubble jet) drop on demand type printers. Print samples wereallowed to dry for at least one hour before evaluation or the drying wasaccelerated by oven drying for 10 minutes at 85° C.

[0037] After application, the print was evaluated as follows:

[0038] Optical density (OD) was measured on a Macbeth 1200 ColorChecker. Wet rub resistance (WR) was measured by wiping a wetted Kleenexfacial tissue across a 2.5 cm block of solid, filled print area. Theresistance to smudging was rated on a 1 to 5 scale where 5 indicates nosmudging and 1 indicated smudging equal to the pigmented Hewlett Packardink sold for that specific printer. Highlighter resistance was rated byusing commercially available acidic and alkaline highlighters tohighlight a printed text area. The rating indicates the number of timesthe highlighter was wiped over the same text area before significantsmudging was noted. A maximum of ten highlighter wipes were tried on asample. Responses of 10 can be interpreted as 10 or greater. Printquality was rated by judging the appearance of a printed page ofcombined text and graphics. Edge sharpness, bleed, feathering, wet-rubresistance, highlighter resistance and print operability wereaccumulated into this evaluation. The scale is the linear combination of3 times the optical density, the highlighter performance, the wet rubperformance and the print operability rating. Print operability wasrated by judging the printer performance. Print appearance anduniformity, page after page longevity of print quality and uniformity,nozzle drop outs, print head maintenance problems and the ability tostop and restart were accumulated into this evaluation. The scale rangesfrom 0 to 5 where 0 was inoperable, 1 was poor and 5 was excellent.

Example 1*

[0039] An addition polymer was prepared in accordance with the followinggeneral procedure:

[0040] A three liter flask was charged with 960 g of deionized water,placed under a nitrogen atmosphere, and heated to 85° C. A monomeremulsion consisting of 275 g 2-ethylhexyl acrylate (52 parts), 227 gmethyl methacrylate (43 parts), 27 g methacrylic acid (5 parts), 1.5 gof TREM LF-40 solution (36%, Henkel Corp.), and 177 g deionized waterwas separately prepared. Prior to addition of this emulsion to thekettle, ammonia (24 g of a 4.8%-9.6% aqueous solution), ammoniumpersulfate (11 g of a 9.6% solution), and a 54 nm acrylic polymer seed(22.5 g of a 22.8% solution) were added to the kettle. The monomeremulsion was then fed to the kettle with stirring at a rate of 3.9g/min. for 20 min. along with a solution of 24.6 g of 2.24% aqueousammonium persulfate at a rate of 0.2 g/min., followed by 100 minutes at6.4 and 0.20 g/min., respectively, and a hold period of 20 min. Themixture was then cooled to 60° C., and a mixture of 2.6 g of 0.15%ferrous sulfate followed by 3.2 g of 4.4% t-butyl hydroperoxide and 6.1g of 1.6% sodium formaldehyde sulfoxylate was added and held for 20min., followed by a second identical portion of tBHP and SFS. Themixture was then cooled, filtered, and sufficient 29% aqueous ammoniawas added to adjust the pH to a range of 8.0-9.0 (final polymerbinder=30% by weight polymer solids, average diameter 270 nm, Tg=−20°C., and pH 8.2).

Examples 2 to 53

[0041] The procedure recited above was repeated except that the monomeremulsion was adjusted as indicated below:

Example 2 (Comparative)

[0042] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts hydroxyethylcellulose (final polymer binder=30% byweight polymer solids, average diameter 380 nm, Tg=−20° C., and pH 8.1);

Example 3 (Comparative)

[0043] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts polyvinyl alcohol (final polymer binder=30% byweight polymer solids, average diameter 597 nm, Tg=−20° C., and pH 8.1);

Example 4 (Comparative)

[0044] 45.6 parts by weight butylacrylate, 52.4 parts by weightmethylmethacrylate, 1 part by weight adhesion promoter, and 1 part byweight methacrylic acid was polymerized in the presence of 0.5 partssodium lauryl sulfate (final polymer binder=30% by weight polymersolids, average diameter 120 nm, Tg=−20° C., and pH 8.1);

Example 5 (Comparative)

[0045] 19 parts by weight butylacrylate, 80 parts by weight vinylacetate, and 0.6 parts by weight hydroxyethyl cellulose, was polymerizedin the presence of 1.5 parts mixed anionic and non-ionicnon-polymerizable surfactants [(final polymer binder=30% by weightpolymer solids, average diameter 220 nm, Tg=−20° C., and pH 8.1);

Example 6 (Comparative)

[0046] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight sodium lauryl sulphate (final polymerbinder=30% by weight polymer solids, average diameter 265 nm, Tg=−20°C., and pH 8.1);

Example 7 (Comparative)

[0047] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight sodium lauryl sulphate (final polymerbinder=30% by weight polymer solids, average diameter 265 nm, Tg=−20°C., and pH 8.1).

Example 8*

[0048] 52 parts by weight ethylhexyl acrylate, 47 parts by weightmethylmethacrylate, and 1 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 270 nm, Tg=−20° C., and pH 9.4).

Example 9*

[0049] 52 parts by weight ethylhexyl acrylate, 45.5 parts by weightmethylmethacrylate, and 2.5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 261 nm, Tg=−20° C., and pH 9.4).

Example 10*

[0050] 52 parts by weight ethylhexyl acrylate, 44 parts by weightmethylmethacrylate, and 4.0 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 254 nm, Tg=−20° C., and pH 9.3).

Example 11*

[0051] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5.0 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=30% byweight polymer solids, average diameter 270 nm, Tg=−20° C., and pH 8.2).

Example 12*

[0052] 52 parts by weight ethylhexyl acrylate, 41 parts by weightmethylmethacrylate, and 7.0 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 269 nm, Tg=−20° C., and pH 8.0).

Example 13*

[0053] 52 parts by weight ethylhexyl acrylate, 39 parts by weightmethylmethacrylate, and 9.0 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 261 nm, Tg=−20° C., and pH 9.4).

Example 14*

[0054] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40 (final polymer binder=30% byweight polymer solids, average diameter 270 nm, Tg=−20° C., and pH 8.2).

Example 15*

[0055] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight TREM LF-40 (final polymer binder=29% byweight polymer solids, average diameter 255 nm, Tg=−20° C., and pH 8.0).

Example 16

[0056] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight allylammonium Lauryl-12EO-phosphate(Stepan X-2263-26; final polymer binder=29% by weight polymer solids,average diameter 271 nm, Tg=−20° C., and pH 8.3).

Example 17

[0057] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight allylammonium Lauryl-7EO-phosphate(Stepan X-2263-27b; final polymer binder=30% by weight polymer solids,average diameter 270 nm, Tg=−20° C., and pH 9.0).

Example 18

[0058] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight allylammonium Lauryl-3EO-phosphate(Stepan X-2263-28b; final polymer binder=29% by weight polymer solids,average diameter 268 nm, Tg=−20° C., and pH 8.7).

Example 19

[0059] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight allylammonium linear-dodecyl benzenesulfonate (Stepan AU-1; final polymer binder=29% by weight polymersolids, average diameter 258 nm, Tg=−20° C., and pH 9.0).

Example 20

[0060] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight allylammonium lauryl-sulfate (StepanAU-5; final polymer binder=29% by weight polymer solids, averagediameter 245 nm, Tg=−20° C., and pH 9.0).

Example 21

[0061] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight allyl ammonium alkylether-sulfate(Stepan NMS-7; final polymer binder=29% by weight polymer solids,average diameter 265 nm, Tg=20° C., and pH 9.0).

Example 22*

[0062] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight ammonium Di-(tricyclo(5.2.1.0 2,6)dec-3-en-(8 or 9)oxyethyl) sulfosuccinate; final polymer binder=29% byweight polymer solids, average diameter 270 nm, Tg=−20° C., and pH 8.6).

Example 23*

[0063] 52 parts by weight ethylhexyl acrylate, 43 parts by weightmethylmethacrylate, and 5 parts by weight methacrylic acid in thepresence of 0.2 parts by weight ammonium Di-(tricyclo(5.2.1.0 2,6)dec-3-en-(8 or 9) sulfosuccinate; final polymer binder=28% by weightpolymer solids, average diameter 270 nm, Tg=−20° C., and pH 8.8).

Example 24*

[0064] 52 parts by weight ethylhexyl acrylate, 45.5 parts by weightmethylmethacrylate, and 2.5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40, and 35 g of 29% polymericseed particles of 54 nm size (final polymer binder=29% by weight polymersolids, average diameter 217 nm, Tg=−20° C., and pH 9.2).

Example 25*

[0065] 52 parts by weight ethylhexyl acrylate, 45.5 parts by weightmethylmethacrylate, and 2.5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40, and 23.5 g of 23% polymericseed particles of 54 nm size (final polymer binder=29% by weight polymersolids, average diameter 261 nm, Tg=−20° C., and pH 9.4).

Example 26*

[0066] 52 parts by weight ethylhexyl acrylate, 45.5 parts by weightmethylmethacrylate, and 2.5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40, and 47.3 g of 35% polymericseed particles of 95 nm size (final polymer binder=28% by weight polymersolids, average diameter 280 nm, Tg=−20° C., and pH 8.6).

Example 27*

[0067] 52 parts by weight ethylhexyl acrylate, 45.5 parts by weightmethylmethacrylate, and 2.5 parts by weight methacrylic acid in thepresence of 0.1 parts by weight TREM LF-40, and 33.5 g of 32% polymericseed particles of 95 nm size (final polymer binder=29% by weight polymersolids, average diameter 323 nm, Tg=−20° C., and pH 9.2).

Example 28*

[0068] In a similar manner to example 1 except 59 parts by weightethylhexyl acrylate, 36 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=29% by weight polymer solids, averagediameter 262 nm, Tg=−31° C., and pH 9.0).

Example 29*

[0069] In a similar manner to example 28 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=29% by weight polymer solids, averagediameter 263 nm, Tg=−20° C., and pH 9.0).

Example 30*

[0070] In a similar manner to example 28 with 45 parts by weightethylhexyl acrylate, 50 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=29% by weight polymer solids, averagediameter 271 nm, Tg=−6° C., and pH 8.0).

Example 31*

[0071] In a similar manner to example 28 with 40 parts by weightethylhexyl acrylate, 55 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=29% by weight polymer solids, averagediameter 263 nm, Tg=0° C., and pH 8.4).

Example 32*

[0072] In a similar manner to example 28 with 30 parts by weightethylhexyl acrylate, 65 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=30% by weight polymer solids, averagediameter 276 nm, Tg=+20° C., and pH 8.8).

Example 33*

[0073] In a similar manner to example 28 with 18 parts by weightethylhexyl acrylate, 77 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=30% by weight polymer solids, averagediameter 289 nm, Tg=+40° C., and pH 8.8).

Example 34*

[0074] In a similar manner to example 28 with 8 parts by weightethylhexyl acrylate, 87 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.2 parts by weight TREMLF-40, (final polymer binder=30% by weight polymer solids, averagediameter 261 nm, Tg=+60° C., and pH 8.8).

Example 35*

[0075] In a similar manner to example 29 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5 partsby weight methacrylic acid in the presence of 0.1 parts by weight TREMLF-40, (final polymer binder=30% by weight polymer solids, averagediameter 270 nm, Tg=−20° C., and pH 8.2).

Example 36

[0076] In a similar manner to example 29 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5 partsby weight acrylic acid in the presence of 0.2 parts by weight StepanAU-1 (final polymer binder=29% by weight polymer solids, averagediameter 296 nm, Tg=−20° C., and pH 8.0). 261 nm, Tg=+60° C., and pH8.8).

Example 37*

[0077] In a similar manner to example 29 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5 partsby weight oligomeric acrylic acid (Mw=1400, prepared according to theprocess disclosed in U.S. Pat. No. 5,710,227 in the presence of 0.1parts by weight TREM LF-40, (final polymer binder=28% by weight polymersolids, average diameter 261 nm, Tg=−20° C., and pH 9.2). 261 nm,Tg=+60° C., and pH 8.8).

Example 38

[0078] In a similar manner to example 29 with 52 parts by weightethylhexyl acrylate, 43.5 parts by weight methylmethacrylate, 3.0 partsby weight acrylic acid, and 1.5 parts by weight itaconic acid in thepresence of 0.2 parts by weight Stepan AU-1 (final polymer binder=30% byweight polymer solids, average diameter 276 nm, Tg=−20° C., and pH 8.5).

Example 39

[0079] In a similar manner to example 29 with 52 parts by weightethylhexyl acrylate, 43.5 parts by weight methylmethacrylate, and 5parts by weight itaconic acid in the presence of 0.2 parts by weightStepan AU-1 (final polymer binder=29% by weight polymer solids, averagediameter 264 nm, Tg=−20° C., and pH 8.6).

Example 40*

[0080] In a similar manner to example 14 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5.0parts by weight methacrylic acid in the presence of 0.2 parts by weightTREM LF-40 (final polymer binder=30% by weight polymer solids, averagediameter 270 nm, Tg=−20° C., and pH 8.2).

Example 41

[0081] In a similar manner to example 14 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5.0parts by weight methacrylic acid in the presence of 0.1 parts by weightStepan AU-1 (final polymer binder=29% by weight polymer solids, averagediameter 270 nm, Tg =−20° C., and pH 9.6).

Example 42

[0082] In a similar manner to example 41 with 52 parts by weightethylhexyl acrylate, 42 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 1 part by weight 2-hydroxyethylmethacrylate (HEMA) in the presence of 0.2 parts by weight Stepan AU-1(final polymer binder=29% by weight polymer solids, average diameter 254nm, Tg=−20° C., and pH 9.0).

Example 43

[0083] In a similar manner to example 42 with 52 parts by weightethylhexyl acrylate, 41 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 2 parts by weight 2-hydroxyethylmethacrylate (HEMA) in the presence of 0.2 parts by weight Stepan AU-1(final polymer binder=29% by weight polymer solids, average diameter 272nm, Tg=−20° C., and pH 9.2).

Example 44

[0084] In a similar manner to example 42 with 52 parts by weightethylhexyl acrylate, 39 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 4 parts by weight 2-hydroxyethylmethacrylate (HEMA) in the presence of 0.2 parts by weight Stepan AU-1(final polymer binder=30% by weight polymer solids, average diameter 275nm, Tg=−20° C., and pH 9.0).

Example 45

[0085] In a similar manner to example 42 with 52 parts by weightethylhexyl acrylate, 35 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 8 parts by weight 2-hydroxyethylmethacrylate (HEMA) in the presence of 0.2 parts by weight Stepan AU-1(final polymer binder=29% by weight polymer solids, average diameter 250nm, Tg=−20° C., and pH 8.9).

Example 46

[0086] In a similar manner to example 42 with 52 parts by weightethylhexyl acrylate, 42 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 1 part by weight 2-hydroxyethyl acrylate(HEA) in the presence of 0.2 parts by weight Stepan AU-1 (final polymerbinder=29% by weight polymer solids, average diameter 266 nm, Tg=−20°C., and pH 9.0).

Example 47

[0087] In a similar manner to example 46 with 52 parts by weightethylhexyl acrylate, 41 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 2 parts by weight 2-hydroxyethyl acrylate(HEA) in the presence of 0.2 parts by weight Stepan AU-1 (final polymerbinder=29% by weight polymer solids, average diameter 274 nm, Tg=−20°C., and pH 8.7).

Example 47

[0088] In a similar manner to example 46 with 52 parts by weightethylhexyl acrylate, 41 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 2 parts by weight 2-hydroxyethyl acrylate(HEA) in the presence of 0.2 parts by weight Stepan AU-1 (final polymerbinder=29% by weight polymer solids, average diameter 274 nm, Tg=−20°C., and pH 8.7).

Example 48

[0089] In a similar manner to example 46 with 52 parts by weightethylhexyl acrylate, 39 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 4 parts by weight 2-hydroxyethyl acrylate(HEA) in the presence of 0.2 parts by weight Stepan AU-1 (final polymerbinder=29% by weight polymer solids, average diameter 258 nm, Tg=−20°C., and pH 8.7).

Example 49

[0090] In a similar manner to example 46 with 52 parts by weightethylhexyl acrylate, 35 parts by weight methylmethacrylate, 5.0 parts byweight methacrylic acid, and 8 parts by weight 2-hydroxyethyl acrylate(HEA) in the presence of 0.2 parts by weight Stepan AU-1 (final polymerbinder=29% by weight polymer solids, average diameter 225 nm, Tg=−20°C., and pH 8.3).

Example 50*

[0091] In a similar manner to example 14 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5.0parts by weight methacrylic acid in the presence of 0.1 parts by weightTREM LF-40 (final polymer binder=30% by weight polymer solids, averagediameter 270 nm, Tg=−20° C., and pH 8.2). This sample was used as is.

Example 51*

[0092] In a similar manner to example 14 with 52 parts by weightethylhexyl acrylate, 43 parts by weight methylmethacrylate, and 5.0parts by weight methacrylic acid in the presence of 0.1 parts by weightTREM LF-40 (final polymer binder=30% by weight polymer solids, averagediameter 270 nm, Tg=−20° C., and pH 8.2). To a portion of this emulsionwas post-added 1 equivalent weight of LiOH, and the NH3 liberated wasallowed to dissipate under enclosed air flow.

Example 52*

[0093] To a portion of example 50 emulsion was post-added 1 equivalentweight of KOH, and the NH3 liberated was allowed to dissipate underenclosed air flow.

Example 53*

[0094] To a portion of example 50 emulsion was post-added 1 equivalentweight of NaOH, and the NH3 liberated was allowed to dissipate underenclosed air flow.

[0095] Evaluation 1

[0096] This series of evaluations was prepared to demonstrate theimproved print quality achieved when ink jet inks of the presentinvention are compared against ink jet inks comprising binderscontaining no polymerized surfactant monomer. The results are presentedin Table 1.

[0097] From Table 1, it may be seen that the use of the polymerizablesurfactant, Trem LF-40, in Polymer Binder of Example 1* gave aremarkable improvement in print quality than any of the othercomparative systems. It is important to note that the non-polymerizablesurfactant system used in Polymer Binder of Example 8 yielded poor printquality. It is also interesting to note that the optical density (OD)for the Polymer Binder of Example 1 was the best of the series as well.

[0098] Evaluation 2

[0099] This series of evaluations was prepared to demonstrate the effectof varying the acid level in the polymer binder of the presentinvention. The results are presented in Table 2.

[0100] The results in Table 2 indicate that OD, HR, and WR continue toimprove as the acid level was increased, the print operability waspoorer at 9% than at 5 or 7% MAA. While higher levels may be usable,especially with other acid monomers, we found the 5 to 7% level to beoptimum for the overall balance of properties. TABLE 1 Inkjet PrintOptical Highlighter Wet Print Stabilization Formulation Quality DensityResistance Rub Operability HP Printer Example 1* TREM 1 3.9 1.18 3 3 3540 Example 2 HEC 1 2.8 1.11 3 3 2 540 Example 3 PVOH 1 0 NA NA NA 0 540Example 4 SLS 1 0 NA NA NA 0 540 Example 5 PVOH 1 0 NA NA NA 0 540Example 6 SLS 1/2 2.8 1.12 3 3 3 540/690C Example 7 SLS 1/2 2.8 1.13 3 33 540/690C

[0101] TABLE 2 Long Term Acid/ Inkjet Print Optical Highlighter WetPrintability Print HP % Formulation Quality Density Resistance Rub (# ofprints) Operability Printer Example MAA 2 3.6 1.40 8 2 NA 0 690C  8* 1%Example 2.5 2 4.0 1.36 8 3 NA 1 690C  9* Example 4.0 2 3.8 1.38 8 2 NA 1690C 10* Example 5.0 2 5.3 1.39 10  3   1000+ 4 690C/890C 11* Example7.0 2 4.8 1.44 9 3  500 3 690C/890C 12* Example 9.0 2 4.9 1.54 10  3  502 690C/890C 13*

[0102] Evaluation 3

[0103] This series of evaluations was prepared to demonstrate the effectof varying the polymerizable surfactant monomer in the monomer mixtureused to prepare the polymer binder of the present invention. The resultsare presented in Table 3. The results in Table 3 indicate all inks wereprintable and had good properties.

[0104] Evaluation 4

[0105] This series of evaluations was prepared to demonstrate the effectof varying the particle size of the polymer binder used in the inks ofthe present invention. The results are presented in Table 4.

[0106] Particle sizes from 200 to 350 nm were evaluated. The results inTable 4 show that over this narrow range of particle size, all sampleswere printable. The print quality of the 250 nm variant was slightlybetter as was its HR and WR. OD seems to reach a minimum in this range.We could expect acceptable good print quality over a wider range ofparticle size.

[0107] Evaluation 5

[0108] This series of evaluations was prepared to demonstrate the effecton the ink of the present invention of varying the carboxylic acidmonomer used in the monomer mix from which the polymer binder is made.The results are presented in Table 5.

[0109] The results in Table 5 show that MAA appears to be the best forthe overall balance of OD, WR, HR and print quality. TABLE 3 5% MAA, Tg= −20, 250 nm Inkjet Print Optical Highlighter Wet Print SurfactantType/level Formulation Quality Density Resistance Rub Operability HPPrinter Example 14* TREM LF-40/0.1% 2 5.1 1.45 10 3 4 690C/890C Example15* TREM LF-40/0.2% 2 4.3 1.38  7 3 3 690C Example 16 STEPAN2263-26/0.1% 2 5.3 1.46 10 4 3 690C Example 17 STEPAN 2263-27B/0.2% 24.8 1.43 10 2 3 690C Example 18 STEPAN 2263-28B/0.1% 2 5.4 1.49 10 4 3690C Example 19 STEPAN AU-1/0.2% 2 5.6 1.50 10 4 4 690C/890C Example 20STEPAN AU-5/0.2% 2 5.4 1.49 10 4 3 690C Example 21 STEPAN NMS-7/0.2% 25.1 1.45 10 3 3 690C Example 22* ammonium di-(tricyclo(5.2.1.0 2,6) 25.1 1.41 10 3 3 690C dec-3-en-(8 or 9)oxyethyl) sulfosuccinate Example23* ammonium di-(tricyclo(5.2.1.0 2,6) 2 4.3 1.42  6 4 3 6900dec-3-en-(8 or 9) sulfosuccinate

[0110] TABLE 4 Optical Highlighter HP Particle Size Inkjet FormulationPrint Quality Density Resistance Wet Rub Print Operability PrinterExample 24* 217 2 3.5 1.38 6 2 2 690C Example 25* 261 2 4.5 1.36 8 3 3690C Example 26* 280 2 3.0 1.34 5 1 2 690C Example 27* 323 2 3.6 1.44 53 2 690C

[0111] TABLE 5 Highlighter Print HP Acid Type Surfactant InkjetFormulation Print Quality Optical Density Resistance Wet Rub OperabilityPrinter Example 35* MAA TREM, 0.1% 2 5.6 1.40 10 4 4 690C/890C Example36 AA AU-1, .2% 2 4.5 1.38  7 4 3 690C Example 37* o-AA TREM, 0.1% 2 4.71.32 10 3 2 690C Example 38 1.5% IA/ AU-1, .2% 2 5.1 1.42 10 3 3 690C3.0% AA Example 39 IA AU-1, .2% 2 5.1 1.42 10 3 3 690C

[0112] Evaluation 6

[0113] This series of evaluations was prepared to demonstrate the effectof varying the glass transition temperature of the polymer binder usedin the inks of the present invention. The results are presented in Table6.

[0114] The results in Table 6 show that Tg has little effect on printoperability. OD appears to improve with higher Tg, and HR and WR appearto improve with lower Tg. The WR and HR performance improves as Tg islowered to somewhere between −6C and −20C (between ca. 15 and 40Cdegrees below ambient temperature). Below this point, the WR and HR donot improve. Using a coalescing solvent and/or a high temperature fuser,we can get outstanding WR performance from the Tg=60C sample. Thereappears to be no inherent limit on how far one can increase the Tg andstill get adequate WR using coalescing/fusing of the printed ink.

[0115] Evaluation 7

[0116] This series of evaluations was prepared to demonstrate the effectof varying the hydrophilic nature of the polymer binder used in the inksof the present invention. The results are presented in Table 7.

[0117] Hydrophilic monomers HEA and HEMA were added to the polymerbackbone composition in an attempt to improve print quality. Theexpectation was that a more hydrophilic composition would improve therewet of material encrusted on the printhead and possibly improve thelatex particle dispersion as well. Our data in Table 7 shows that WR,HR, OD and print quality all become poorer as the level of hydrophilicmonomer is increased. However, acceptable performance can be obtained inthe presence of these monomers. TABLE 6 Inkjet Print Quality OpticalDensity Highlighter Resistance Wet Rub Tg Formulation (fused/unfused)(fused/unfused) (fused/unfused) (fused/unfused) Print Operability HPPrinter Example 28* −31 2 5.0 1.39 10 3 3 690C Example 29* −20 2 5.31.40 10 3 4 690C Example 30* −6 2 4.6 1.45  8 3 3 690C Example 31* 0 23.3/2.6 1.44/1.45 3/2 4/2 690C Example 31A* 0 2 3.8/2.6 1.44/1.46 5/24/2 Example 32* 20 2 3.4/2.1 1.53/1.47 3/1 4/1 690C Example 33* 40 23.6/2.1 1.49/1.46 4/1 4/1 690C Example 34* 60 2 4.1/2.2 1.50/1.46 6/14/1 690C

[0118] TABLE 7 Inkjet Print Optical Highlighter Monomer FormulationQuality Density Resistance Wet Rub Print Operability HP Printer Example40* None 2 5.6 1.40 10 4 0.1% TREM LF-40 4 690C Example 41 None 2 5.31.39 10 4 3 690C Example 42 1% HEMA 2 5.1 1.40 10 4 2 690C Example 43 2%HEMA 2 5.1 1.40 10 4 2 690C Example 44 4% HEMA 2 4.3 1.38 8 3 2 690CExample 45 8% HEMA 2 4.2 1.30 8 3 2 690C Example 46 1% HEA 2 4.6 1.40 93 2 690C Example 47 2% HEA 2 4.6 1.43 8 4 2 690C/890C Example 48 4% HEA2 4.2 1.33 7 4 2 690C Example 49 8% HEA 2 0 NA NA NA 0

[0119] Evaluation 8

[0120] This series of evaluations was prepared to demonstrate the effectof varying the binder neutralization in the inks of the presentinvention. The results are presented in Table 8.

[0121] All previous binder preparations were made with ammonia forin-process neutralization. In this series, we used different alkalimetal hydroxides to complete the neutralization of the formulated inks.Some advantages were seen for ammonia and sodium for OD, WR and printquality.

Evaluation 9

[0122] This series of evaluations was prepared to demonstrate the effectof varying the pigment used in the inks of the present invention. Theresults are presented in Table 9. The results in Table 9 suggest thatthe effects that we have seen with carbon black pigmented inks of thepresent invention are repeatable with other pigments. TABLE 8 InkjetPrint Optical Highlighter Wet Base Formulation Quality Densityresistance Rub Print Operability HP Printer Example 50* NH3 2 5.3 1.4110 4 3 690C Example 51* LiOH (post add) 2 4.9 1.25 10 4 2 690C Example52* KOH (post add) 2 4.7 1.27 10 3 2 690C Example 53* NaOH. (post add) 25.3 1.37 10 4 3 690C

[0123] TABLE 9 Print Ink Formulation gms Dispersion Color Operabilityn-MP 1.6 cyan - Polytribo Acryjet 157 2 PEG 1.0 magenta - PolytriboAcryjet 127 2 EG-1 0.5 yellow - Polytribo Acryjet 747 2 Propanediol 1.2Dispersant 6.2 Surfynol 104E 0.1 Example 50 5.0 DI water 14.2

1. A polymeric binder suitable for use in an ink composition, comprisinga colorant and a polymeric binder, wherein the polymeric binder is anemulsion-polymerized addition copolymer formed from a monomer mixturecomprising ethylenically unsaturated monomers including from more than 4to 15 wt % based on the weight of said mixture of at least oneethylenically unsaturated carboxylic acid functional monomer, and from0.05 to 5 wt % based on the weight of said mixture of at least onepolymerizable surfactant monomer comprising hydrophobic and hydrophilicfunctional groups, wherein said hydrophobic functional group comprises apolymerizable group within it.
 2. A polymeric binder as claimed in claim1, wherein the polymerizable surfactant comprises a polymerizable groupselected from (meth)acryl and (meth)allyl.
 3. A polymeric binder asclaimed in claim 2, wherein the polymerizable surfactant is selectedfrom the group of polymerizable surfactant monomers consisting ofnonylphenoxy propenyl polyethoxylated sulphate; sodium alkyl allylsulphosuccinate; ammonium di-(tricyclo(5.2.1.0 2,6) dec-3-en-(8 or9)oxyethyl) sulfosuccinate; and ammonium di-(tricyclo(5.2.1.0 2,6)dec-3-en-(8 or 9) sulfosuccinate.
 4. A polymeric binder as claimed inclaim 1, wherein the acid functional monomer is one or more monomersselected from the group consisting of C₃ to C₂₀ ethylenicallyunsaturated carboxylic acids, their basic salts, and mixtures of suchmonomers.
 5. A polymeric binder as claimed in claim 1, wherein saidmonomer mixture comprises one or more monomers selected from the groupof monomers consisting of substituted and unsubstituted (C₁ to C₅₀)alkyl (meth) acrylates, styrene and substituted styrenes, vinylacrylates, vinyl acetates, fluoromethacrylates, acrylamide, substitutedacrylamides, and methacrylamides, substituted methacrylamides.
 6. An inkcomposition comprising a colorant and a polymeric binder wherein thepolymeric binder is an emulsion-polymerized addition copolymer formedfrom a monomer mixture comprising ethylenically unsaturated monomersincluding from more than 4 to 15 wt % based on the weight of saidmixture of at least one ethylenically unsaturated carboxylic acidfunctional monomer, and from 0.05 to 5 wt % based on the weight of saidmixture of at least one polymerizable surfactant monomer comprisinghydrophobic and hydrophilic functional groups, wherein said hydrophobicfunctional group comprises a polymerizable group within it..
 7. An inkcomposition as claimed in claim 6, wherein said ink composition is anink jet ink.
 8. A method of improving the print quality of an inkcomposition, which method comprises formulating said composition byincorporating therein a polymeric binder formed by polymerizing amonomer mixture comprising ethylenically unsaturated monomers includingfrom more than 4 to 15 wt % based on the weight of said mixture of atleast one ethylenically unsaturated carboxylic acid functional monomer,and from 0.05 to 5 wt % based on the weight of said mixture of at leastone polymerizable surfactant monomer comprising hydrophobic andhydrophilic functional groups, wherein said hydrophobic functional groupcomprises a polymerizable group within it..
 9. A method as claimed inclaim 8, wherein said ink composition is an ink jet ink.
 10. Use in thepreparation of an ink composition of a polymeric binder formed bypolymerizing a monomer mixture comprising ethylenically unsaturatedmonomers including from more than 4 to 15 wt % based on the weight ofsaid mixture of at least one ethylenically unsaturated carboxylic acidfunctional monomer, and from 0.05 to 5 wt % based on the weight of saidmixture of at least one polymerizable surfactant monomer comprisinghydrophobic and hydrophilic functional groups, wherein said hydrophobicfunctional group comprises a polymerizable group within it, to improvethe print quality of said ink composition.
 11. Use as claimed in claim10, wherein said ink composition is an ink jet ink composition.